Wheat is mainly grown for use in human food production. The use of wheat in animal feeds is usually limited to times when wheat is competitively priced with corn or other grains. The high price of corn has increased the interest in the potential use of wheat in poultry and swine feeds. It is important to understand some of the characteristics of wheat to make proper feeding decisions when it is economically advantageous to use wheat.
There are two types of wheat typically available: hard red winter wheat and soft red winter wheat. Pennsylvania, Ohio, Illinois, and Indiana are leading producers of soft red winter wheat varieties, which are manufactured into cake, cracker, and biscuit flours. In the Central and Great Plains states like Kansas, Oklahoma, Texas, and Nebraska, hard red winter wheat is grown for use in breads.
A nutrient comparison of hard red winter wheat, soft red winter wheat, and corn is shown in Table 1.
|Table 1. Nutrient Content of Corn, Hard Red Winter Wheat and Soft Red Winter Wheat|
|Nutrient||Corn||Hard Red Wheat||Soft Red Wheat|
|Crude Protein, %||7.8||13.1||10.6|
|Methionine + Cystine, %||.33||.50||.40|
|Crude fat, %||3.8||1.9||1.7|
|Av. Phosphorus, %||0.05||0.20||0.15|
Wheat contains less energy, but more protein and amino acids (methionine + cystine and lysine) than corn. Hard red winter wheat contains more phosphorus than corn, and both wheat types contain more available phosphorus than corn. Hard red winter wheat contains more protein and amino acids than soft red winter wheat but contains less energy.
Wheat can be successfully used in poultry and swine feeds.
Although wheat contains more protein and lysine than corn, the balance of amino acids in wheat is rather poor. This means poultry and swine diets formulated with wheat should be balanced on an amino acid (methionine + cystine and/or lysine) basis, not a crude protein basis. Replacing corn with wheat on an equal protein basis decreases the dietary amino acid content of the feed and can result in poorer animal performance. Research from the University of Kentucky suggests wheat has a similar value to corn when diets are formulated on an equal amino acid and energy basis. The feeding value of the two types of wheat appears to be similar in poultry and swine when feeds are balanced on an amino acid basis.
Wheat available for use in animal feed is typically a “feed-grade wheat” and is often product rejected for human food production. Low test weight, sprouted grains, and the presence of mycotoxins are all factors which prevent the use of wheat in human foods. These same factors can reduce the nutritional value of wheat or even make it unsuitable for use in poultry and swine diets.
Wheat stressed by weather or disease often has lighter test weights. As the bushel weight of wheat decreases, the energy level of wheat also decreases. If a feed contains low test weight wheat (low test weight not taken into account), animals compensate by consuming more feed. Growth rate is often not influenced, but poorer feed efficiency can result.
Low test weight wheat can be used in poultry and swine diets, but the reduction in energy needs to be taken into account to prevent a reduction in performance. Fat supplementation can be used, or light test weight wheat can be blended with normal test weight grain to account for the reduction in energy content. The price paid for light test weight wheat should take the reduced energy content into account.
High rainfall just before harvest can cause wheat to sprout on the head. Sprouted grain typically contains less energy than non-sprouted grain. The lower energy level makes the feeding recommendations for sprouted wheat similar to those for light test weight wheat.
Fungal diseases of wheat can reduce the feeding value of wheat. Scab can be caused by several fungi in the genus, Fusarium. Kernels infected with scab tend to be shriveled, chalky white, and some grains will be pinkish in color. Zearalenone and vomitoxin (DON) have been the mycotoxins associated with scabby wheat.
Zearalenone is commonly associated with reproductive problems in swine and the presence of vomitoxin in feed typically reduces feed consumption. The level of zearalenone and vomitoxin in the complete feed of swine should each be less than 1 ppm. The level of vomitoxin in poultry feeds should be less than 5 ppm. Since wheat available for animal feed use has typically been rejected for use in human foods, it is important to check for mycotoxin levels in wheat.
Wheat containing garlic bulblets can’t be used for human consumption. Wheat contaminated with garlic is subject to a rather severe price reduction. The performance of poultry and swine does not appear to be influenced by garlicky wheat containing up to 160 bulblets per pound. Wheat severely contaminated with garlic (> 600 bulblets per pound) is unpalatable to young pigs and can cause a garlicky flavor in pork. However, even severely contaminated wheat can be diluted with other grains to overcome the potential problems associated with garlicky wheat.
From a manufacturing standpoint, the use of wheat does improve pellet durability. The proteins in wheat help to bind ingredients during the pelleting process. Wheat can become very floury and can be somewhat unpalatable if ground too finely. Feeds containing finely ground wheat may flow poorly in feeders. For poultry, finely ground wheat can cause beak impaction due to the protein in wheat becoming sticky and adhering to the beak. In swine, finely ground wheat may increase the incidence of stomach ulcers.
Wheat should be coarsely ground and each kernel must be broken. A hammer mill with a ¼ inch opening in the screen and a reduced hammer speed can result in a desirable particle size. If all else fails, the amount of wheat added to the diet can also be limited in an effort to overcome some of the difficulties associated with handling diets containing finely ground wheat.
Wheat can be successfully used in poultry and swine feeds. Keep the following points in mind when considering the use of wheat.
1. The decision to use wheat should be based on economics.
2. Formulate diets containing wheat on lysine basis rather than a protein basis.
3. The test weight of wheat should be determined and wheat should be examined for sprouted grains and the presence of garlic bulblets.
4. Wheat should be tested for the zearalenone and vomitoxin. The complete feed of swine should contain less than 1 ppm of each of these mycotoxins. Poultry diets should contain less than 5 ppm of vomitoxin.
5. Coarsely grind wheat and make sure every kernel is broken.
6. Replace only a portion of your grain if finely ground wheat is a potential problem.
7. If you make a switch from corn to wheat, gradually increase the level of wheat in the diet to help animals adapt to wheat containing diets.